Date: Mon, 9 Jun 2008 00:18:32 +0200 (CEST) From: Wojciech Puchar <wojtek@wojtek.tensor.gdynia.pl> To: Dick Hoogendijk <dick@nagual.nl> Cc: freebsd-questions@freebsd.org Subject: Re: FreeBSD + ZFS on a production server? Message-ID: <20080609001010.G59013@wojtek.tensor.gdynia.pl> In-Reply-To: <20080608230131.00003da7@westmark> References: <1a5a68400806080604ped08ce8p120fc21107e7de81@mail.gmail.com> <20080608215648.Q9779@wojtek.tensor.gdynia.pl> <20080608230131.00003da7@westmark>
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> ZFS is herre to stay. You better get used to it. at least you could try > to work with it before you make up an opinion. Have you -any- idea at > all what this FS is capable off? if you like - quick summary 1) ZFS "turns random writes into sequential writes" as they say. yes that's true. they just forgot to say that it then turns sequential reads into random reads. simple for anyone that still can use his/her brain. 2) ZFS RAID-z turns your X drives to single drive performance both on read and write. every normal RAID-5 implementation will give you random read speed of X-1 times single drive speed, while slow random write speeds (but still at least half of single drive). but this is advertised as a feature 3) a CPU,cache and memory bandwidth hogging "feature" of checksumming all blocks. thing that are already done in disk hardware. fortunately you can turn this off 4) write anywhere style of writing, just with large buffers it could get large blocks to be written at once if only large continous space are found. quite good (but not that much better than UFS) as long as your drive is mostly empty. 5) incredibly high memory consumption. very high CPU consumption compared to UFS.
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